Three-wire electrical cord connector



sept. 21, 1965 J. c. HoRvATH ETAL 3,208,035

THREE-WIRE ELECTRICAL CORD CONNECTOR Filed April 19, 1965 United StatesPatent O 3,208,035 THREE-WIRE ELECTRICAL CORD CONNECTGR iIohn C.Horvath, Stepney, and Harry R. Gosselin,

Bridgeport, Conn., assignors to Harvey Hubbell,

Incorporated, Bridgeport, Conn., a corporation of Connecticut Filed Apr.19, 1963, Ser. No. 274,211 4 Claims. (Cl. 339-220) This inventionrelates to three-wire cord connectors, and particularly the typeemploying a central contact on each of the two usual connectorcomponents.

In three-wire electrical cord connectors it is known to employ a centralblade contact on one of the connector components and a cooperatingcentral receptacle contact on the other connector component. It is alsoknown to employ a central blade contact on the connector body and houseit in a central passage in the connector body. ln this type ofarrangement, a terminal for the cord wired to the connector body isusually disposed on the interior of the connector body in electricalcontact with the central blade contact. Frequently in three-wireconnectors of this type, the central contacts are grounding contactswhich are wired to a grounding wire of the electrical cord. Normally theterminals for the central contacts include selectively operatedgrounding binding screws. It is, of course, imperative that theconnection between the grounding wire of a cord connected to theconnector components and the terminals of the central contacts be made,otherwise the safety provided by grounding will not be afforded. It itwell known that it is desirable to prevent the inadvertent falling outof the grounding terminal binding screws from their associated contactterminals. It is particularly diflicult to provide a grounding terminalbinding screw for the blade contact on the connector body that is freeof such inadvertent separation.

It is an object of this invention to provide an improved t-hree-wireconnector body wherein the central blade contact mounted thereon isconstructed so as to provide a terminal binding screw that isirremovably mounted, and therefore, which cannot become inadvertentlydisconnected.

It is a further object to provide an improved connector body as setforth in the preceding paragraph which is constructed to permit easy andeconomical assembly.

The above and other objects of this invention will become apparent froma consideration of the following description and claims taken with theaccompanying drawing, wherein:

FIG. 1 is a perspective view of a connector body incorporating theinvention;

FIG. 2 is a perspective View of a connector cap designed to cooperatewith the FIG. 1 connector body;

FIG. 3 is a longitudinal sectional view taken substantially on line 3-3of FIG. 1 and on a larger scale;

FIG. 4 is a sectional view taken substantially on line 4-4 of FIG. 3;

FIG. 5 is an enlarged view of a portion of FIG. 4 showing the details ofthe blade contact-terminal assembly construction and associated parts;

FIG. 6 is a sectional view on line 6-6 of FIG. 7 of an element, viz., atapped bushing, forming a part of the 3,208,035 Patented Sept. 21, 1965ICC blade contact-terminal assembly in its original condition prior toassembly;

FIG. 7 is an end view looking from the right of FIG. 6 thereof;

FIG. 8 is a perspective View of the blade contact forming a part of theblade contact-terminal assembly;

FIG. 9 is a perspective view of a binding screw forming a part of theblade contact-terminal assembly in its original condition;

FIG. l0 is a plan view of a terminal washer forming a part of the bladecontact-terminal assembly, and

FIG. 1l is a somewhat schematic view showing the manner in which thefree end of the terminal binding screw is upset to render it irremovablerelative to its associated tapped bushing.

The invention is particularly well suited for incorporation inthree-wire cord connectors of the miniature type. However, it is notlimited to such an application. In such application, the connectorusually comprises a connector body, illustrated by itself in FIG. 1, anda connector cap, illustrated by itself in FIG. 2, which are constructedand arranged to be selectively detachably connected and interlocked. Theconnector body 10 comprises a housing of rigid electrical insulationmaterial for all of the electrical elements comprising a main part 12and a cover part 14, which are secured together by tie bolts 16 in anyconvenient manner and form an internal chamber 15. |The circular at face18 of the connector body part 12 includes a pair of openings to permitaccess to the heads of tie bolts 16; a central open end of passageway20, and a pair of radially spaced arcuate slot openings 22, 24, thelatter of which is larger than the former. Passageway 20 and openings22, 24 communicate with chamber 15.

Interiorly of the connector body housing there are disposed currentcarrying receptacle contacts 26, 28, forming a part of contact-terminalmembers 30, 32, respectively (see FIG. 4) the members including terminalbinding screws 34, 36 and strain relief ears 38, 40, respectively, whichare disposed in chamber 15. Currentcarrying wires 42, 44 forming a partof the three-wire cord 46 are arranged to extend through an opening incover part 14 and be connected to the binding screws 34 and 36,respectively, in any conventional manner, as by being directed aroundtheir associated strain-relieving ears and then wrapped around thebinding screws. The preceding type of wiring provides electrical currentto the receptacle contacts 26 and 28 in a generally known manner. e

The connector cap 48 is illustrated in FIG. 2 and includes a pair ofmale contact blades 50, 52 of the interlocking type which areconstructed and arranged to have current carrying wires of a cord wiredto them and be inserted into the slot openings 24 and 22, respectively,and engage receptacle contacts 26 and 28 in the connector body to makeelectrical contact therewith. Relative turning of the cap and connectorbody results in interlocking in a generally known manner.

The connector body 10 also includes a centrally mounted male bladecontact disposed in its passageway 20 that is constructed and arrangedto be selectively engaged by a centrally mounted tubular receptaclecontact 54 carried by the connector cap and projecting from the facethereof in a manner similar to that of the male contact blades 50, 52.Interiorly of the connector cap, the tubular contact 54 has terminalmeans formed which is arranged to have a third wire, which may be agrounding wire, of the cord connected to the connector cap wired to it.The tubular contact 54 is arranged to be inserted into the passageway 20in the connector body and to engage and surround the blade contactmounted therein.

The construction of the blade contact and terminal means associated withit forms an important part of the invention, and therefore, will bedescribed in great detail. Essentially, the blade contact and terminalmeans comprises an assembly of economical parts which are constructedand readily assembled in a particular manner to provide a terminalbinding screw associated with the blade contact which is irremovablymounted.

The blade contact-terminal assembly comprises a tapped bushing 56 whichis shown in its original condition in FIGS. 6 and 7 and in its fullyassembled condition in FIGS. 3, 4 and 5. The blade contact-terminalassembly also includes a blade contact member 58, shown by itself inFIG. 8; a terminal washer 60, shown by itself in FIG. 10, and a terminalbinding screw 62 shown in the original condition by itself in FIG. 9.The referred-to elements of the blade contact-terminal assembly may .beformed as a subassembly and the unit mounted on the connector bodyhousing part 1-2. This may be accomplished by assembling these elementson a block 64 of electrical insulation material which, in turn, isassembled to the connector `body part 12, which is also made ofelectrical insulation material. The manner of assembly of the sblock 64to the body part 12 forms no particular part of this invention, but itis effected by associating contact-terminal members 30, 32 in aparticular m-anner to anchor these elements together.

To assemble the blade contact-terminal assembly, the `tappeti bushing 56(see FIGS. 6 and 7), which initially comprises a metallic tubular memberhaving an annular radially outwardly extending flange 66 formed at oneaxial end and an intermediate intern-ally extending flange 68 tapped atits central opening formed near but spaced from .the other .axial end,is inserted through a central circular passage 70 formed in theinsulating block 64 from the right end thereof with relation to FIG.until its -ange 66 abuts the right end of block 64. These parts aredimensioned so that the left end of the bushing 56 projects beyond theleft end of the block 64 at this time in assembly. The terminal washer60 (see FIG. l0) which comprises a at, ring-like portion 72 having ashort peripheral flange 74 formed .around most of its periphery, isslipped onto lche free end of the bushing 56 and the latter is spun overso as to be deformed into its final condition illustrated in FIGS. 3 and5, wherein it has a radially outwardly extending flange 76 formed at itsend opposite the flange 66. Flange 76 abuts the left end of block 64. Atthis point in assembly, the bushing S6 and terminal washer 60 areassembled to the insulating bloc-k 64 by the cooperative action offlanges 66 and 76 on the ends of the block.

The terminal binding screw 62 is shown in its initial condition in FIG.9, and it initially comprises the usual hexagonal head 78 and threadedshank 80 of uniform diameter. Terminal binding screw 62 is threadedlyinserted into the th-readed ange 68 of the bushing 56. This point inassembly is somewhat schematically illustrated in FIG. 1l, wherein theshank 80 of the terminal binding screw is illustrated as being uniformlycylindrical and threaded. In order to render the binding screw 62irremovable relative to the bushing 56, a punch P is inserted, as shownschematically in FIG. 11, through the right end of the bushing 56, andthe free end of the .binding screw shank 80 is deformed to form aradially outwardly extending ange-like upset 82, as c-an be clearly seenin FIG. 5. 'Ilhe diametral relationship of the upset 82 and the threadedflange 68 on the bushing 56 is such that after it has Abeen formed bythe punch P it is not possible by normal turning of the binding screw 62to remove the screw from the bushing 56 because of interference betweenthe upset 82 and the right side of bushing flange 68. Therefore, thescrew is irremovably mounted and cannot be inadvertently disconnectedand lost.

After the terminal binding screw 62 has been assembled to the bushing 56in the foregoing manner, the blade contact member 58, which isillustrated by itself in FIG. 8, is then secured to the bushing 56. Theblade contact member 58 comprises a cylindrical portion 84 having arounded end 86 and a slot 88 extending a substantial dist-ancetherethrough to permit some radial flexure in operation. Contact member58 also includes a mounting portion of Areduced diameter 90 having aplurality of axial splines formed thereon. The diametral relationship ofthe mounting portion 90 of the contact member 58 and the bushing 56 issuch that the contact member can be forcibly inserted into the bushingand the splines will form 4an effective force fit mechanical connectionthere- -between to prevent removal of the contact member in normalusage.

When the blade contact-terminal assembly has been fully assembled on theinsulation block 64, and in turn fully assembled in the connector bodyhousing, the central wire 92 of the cord 46, which extends into chamber15, may be wrapped around the binding screw 62 under its Ihead andforcibly squeezed between the terminal washer 60 and the head 78.

In view `of the foregoing it will be apparent that applicants haveachieved the objects of their invention and that they have provided animproved central blade contact-terminal construction which permits thecapturing of a terminal binding screw on the central blade Contact,which has never been accomplished in prior art devices, because of theinherent diiculty of capturing a screw on the 'blade contacts heretoforeemployed, which we-re integrally formed with their terminal means andprecluded the use of an upsetting tool to form an upset on the terminalscrew to capture it. Certain aspects of our invention are not limited tothe particular details of construction of the example illustrated, andwe contemplate that various and other modifications and applicationswill occur to those skilled in the art. It is, therefore, our intentionthat the appended claims shall cover such modifications and.applications as do not depart from the true spirit and scope of -ourinvention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. An electrical connect-or comprising: a housing of insulationmaterial; a contact mounted thereon; a terminal including a terminalbinding screw for electrically connect-ing a wire to said contact;electrical conducting support means carried by said housing andthreadedly supporting said terminal screw; said contact being separatefrom but rigidly secured to said support means; said terminal bindingscrew being irremovably mounted on said support means; said contact,support means and binding screw being aligned with said contact and saidbinding screw at opposite ends of said support means; and said supportmeans comprising a tubular bushing hav- -ing a pair of radiallyoutwardly extending retaining flanges and an intermediate radiallyinwardly extending iiange centrally open and threaded for receiving saidterminal binding screw.

2. The connector defined in claim 1 wherein said contact includes asplined mounting portion that is disposed in and rigidly attached tosaid bushing.

3. An electrical connector comprising: a housing of insulation material;a chamber formed in the interior of the housing; a passageway in saidhousing communicating with said chamber and the exterior of saidhousing; a tubular bushing supported in said housing and extendingpartially into said chamber and partially into said passageway, andincluding an intermediate radially inwardly extending flange having acentral threaded opening; a contact separate from said bushing, disposedin said passageway and including a mounting portion rigidly secured tosaid bushing; and a terminal binding screw having a head accessible fromsaid chamber and a shank threadedly received in the threaded opening ofsaid bushing flange; `said screw including a radially outwardlyextending flange-like upset formed at the free end of its shank of agreater diameter than that of the threaded opening in said bushing whichis disposed in said bushing on the passageway side of said flange,whereby said screw is irremova'bly mounted on said bushing.

4. The connector dened in claim 3 wherein said mounting portion includessplines and is `force t `into said bushing.

References Cited by the Examiner UNITED STATES PATENTS 2,255,763 9/41Doughman 339-191 X 2,466,997 4/49 Morris 339-211 2,733,418 1/56 Kimble339-255 X 3,066,271 11/62 Carlson 339-14 3,112,973 12/63 Von Holtz339-14 FOREIGN PATENTS 614,486 9/26 France.

379,844 8/23 Germany.

232,384 4/ 25 Great Britain.

JOSEPH D. SEERS, Primary Examiner.

1. AN ELECTRICAL CONNECTOR COMPRISING: A HOUSING OF INSULATION MATERIAL;A CONTACT MOUNTED THEREON; A TERMINAL INCLUDING A TERMINAL BINDING SCREWFOR ELECTRICALLY CONNECTING A WIRE TO SAID CONTACT; ELECTRICALCONDUCTING SUPPORT MEANS CARRIED BY SAID HOUSING AND THREADEDLYSUPPORTING SAID TERMINAL SCREW; SAID CONTACT BEING SEPARATE FROM BUTRIGIDLY SECURED TO SAID SUPPORT MEANS; SAID TERMINAL BINDING SCREW BEINGIRREMOVABLY MOUNTED ON SAID SUPPORT MEANS; SAID CONTACT, SUPPORT MEANSAND BINDING SCREW BEING ALIGNED WITH SAID CONTACT AND SAID BINDING SCREWAT OPPOSITE ENDS OF SAID SUPPORT MEANS; AND SAID SUPPORT MEANSCOMPRISING A TUBULAR BUSHING HAVING A PAIR OF RADIALLY OUTWARDLYEXTENDING RETAINING FLANGES AND AN INTERMEDIATE RADIALLY INWARDLYEXTENDING FLANGE CENTRALLY OPEN THREADED FOR RECEIVING SAID TERMINALBINDING SCREW.